Also all you need is to use your ward skill to write a ward on any surface that can handle it.

Anyone can write a forbidding ward circle using their untrained ward skill. The warder can do the same but he/she can use his higher wards on as many objects as possible. Which is why a warder, given enough time, could ward an entire bridge. The trick is that, those wards are un-powered during the day, and only activate around demons. Which is why you don't have spells per day.